In order to study the evolution of the freezing fringe and final lenses of frost susceptible soils and advance the understanding of frost heave and mechanism of frost heave control, we used an open one-dimensional fro...In order to study the evolution of the freezing fringe and final lenses of frost susceptible soils and advance the understanding of frost heave and mechanism of frost heave control, we used an open one-dimensional frost heave test system of infrared radiation technology, instead of a traditional thermistor method. Temperatures of the freezing fringe and segregated ice were measured in a non-contact mode. The results show that accurate and precise temperatures of ice segregation can be obtained by infrared thermal imaging systems. A self-developed inversion program inverted the temperature field of frozen soils. Based on our analysis of temperature variation in segregated ice and our study of the relationship between temperature and rate of ice segregation in cooling and warming processes during intermittent freezing, the mechanism of decreasing frost heave of frozen soils by controlling the growth of final lenses with an intermittent freezing mode, can be explained properly.展开更多
Ice detecting and measuring technologies used and developed for high voltage transmission lines are introduced in this paper. The Icing Rate Meter developed by Hydro-Quebec, working with the magnetostriction principle...Ice detecting and measuring technologies used and developed for high voltage transmission lines are introduced in this paper. The Icing Rate Meter developed by Hydro-Quebec, working with the magnetostriction principle and regulated by an electronic control system is analyzed and the resonant piezoelectric transducers operated by a microprocessor-controlled electronic circuitry is also analyzed in great detail. It shows that the Icing Rate Meter (IRM) developed by Hydro-Quebec can record the occur- rence and duration of icing events, but has two limitations: information on changes in the rate of icing within each hour is lost and the amount of time consumed during heating cycles is not taken into account. A resonant piezoelectric ice detector can automatically and distinctly sense ice and water films up to 0.5 mm thick. It is a smart ice detection system, which might be used widely.展开更多
The collision of a supercooled water droplet with a surface result an object creates ice accretion on the surface. The icing problem in any cold environments leads to severe damages on aircrafts, and a lot of studies ...The collision of a supercooled water droplet with a surface result an object creates ice accretion on the surface. The icing problem in any cold environments leads to severe damages on aircrafts, and a lot of studies on prevention and prediction techniques for icing have been conducted so far. Therefore, it is very important to know the detail of freezing mechanism of supercooled water droplets to improve the anti-and de-icing devices and icing simulation codes. The icing mechanism of a single supercooled water droplet impacting on an object surface would give us great insights for the purpose. In the present study, we develop a dual-luminescent imaging technique to measure the time-resolved temperature of a supercooled water droplet impacting on the surface under different temperature conditions. We apply this technique to measure the exact temperature of a water droplet, and to discuss the detail of the freezing process.展开更多
基金supported by the Key Project of the National Natural Science Foundation of China (No. 50534040)the Project of the National Natural Science Foundation of China (No. 40471021)
文摘In order to study the evolution of the freezing fringe and final lenses of frost susceptible soils and advance the understanding of frost heave and mechanism of frost heave control, we used an open one-dimensional frost heave test system of infrared radiation technology, instead of a traditional thermistor method. Temperatures of the freezing fringe and segregated ice were measured in a non-contact mode. The results show that accurate and precise temperatures of ice segregation can be obtained by infrared thermal imaging systems. A self-developed inversion program inverted the temperature field of frozen soils. Based on our analysis of temperature variation in segregated ice and our study of the relationship between temperature and rate of ice segregation in cooling and warming processes during intermittent freezing, the mechanism of decreasing frost heave of frozen soils by controlling the growth of final lenses with an intermittent freezing mode, can be explained properly.
文摘Ice detecting and measuring technologies used and developed for high voltage transmission lines are introduced in this paper. The Icing Rate Meter developed by Hydro-Quebec, working with the magnetostriction principle and regulated by an electronic control system is analyzed and the resonant piezoelectric transducers operated by a microprocessor-controlled electronic circuitry is also analyzed in great detail. It shows that the Icing Rate Meter (IRM) developed by Hydro-Quebec can record the occur- rence and duration of icing events, but has two limitations: information on changes in the rate of icing within each hour is lost and the amount of time consumed during heating cycles is not taken into account. A resonant piezoelectric ice detector can automatically and distinctly sense ice and water films up to 0.5 mm thick. It is a smart ice detection system, which might be used widely.
文摘The collision of a supercooled water droplet with a surface result an object creates ice accretion on the surface. The icing problem in any cold environments leads to severe damages on aircrafts, and a lot of studies on prevention and prediction techniques for icing have been conducted so far. Therefore, it is very important to know the detail of freezing mechanism of supercooled water droplets to improve the anti-and de-icing devices and icing simulation codes. The icing mechanism of a single supercooled water droplet impacting on an object surface would give us great insights for the purpose. In the present study, we develop a dual-luminescent imaging technique to measure the time-resolved temperature of a supercooled water droplet impacting on the surface under different temperature conditions. We apply this technique to measure the exact temperature of a water droplet, and to discuss the detail of the freezing process.
